I run cold… always!
So when I packed for Milan, Verona and Venice in November and December, I finally added a merino base layer to my carry-on. It was my first trip ever with one!
Highs went from the low 60s°F (about 16°C) down to the low 40s°F (about 5°C), and nights dropped into the high 30s°F (about 3°C). I wore it under my sweaters on the cold days and on its own on the milder ones.
Below are my picks for the best merino wool base layer, including the tops I own and the tights I wear under skirts and dresses.
Here’s what you’ll learn today:
✅ Which merino base layer to pick if you run cold, and which one if you run warm
✅ Lightweight vs midweight, and which neckline hides best under your sweaters
✅ How I wash mine, how often, and the honest tradeoff with a light color
The Best Merino Wool Base Layer for Women Who Run Cold
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Estimated reading time: 9 minutes
The best merino wool base layer for most women is a thin, fitted long sleeve you can tuck in and hide under a sweater, like the Unbound Merino slim V-neck I wear. Go lightweight for city trips between about 35 and 55°F (2 to 13°C), and midweight like Smartwool 250 for days below freezing or long hours outside.
❄️ Lightweight or Midweight? A Quick Cheat Sheet
A base layer is the thin top (or bottom) that sits against your skin, under your sweater or pants.
Merino is one of the most popular picks for it, because it’s warm for how thin it is and it doesn’t hold onto smells like synthetic fabric does.
Three things decide which one you need: how thick the fabric is, the neckline and the color.
🌡️ Match the thickness to the temperature:
Look for a number called GSM (grams per square meter) on the product page. It tells you how thick the fabric is, and the higher the number, the warmer it is.
✅ Lightweight (about 150 to 200 GSM): city trips from about 35 to 55°F (2 to 13°C), worn under sweaters. This is what I wear.
✅ Midweight (200 – 250 GSM): days in the 20s to low 30s°F (about minus 6 to 0°C), or long hours outside at Christmas markets or in ski towns.
✅ Heavyweight (over 250 GSM): snow sports and serious cold. Most city trips don’t need it.
For example, the Unbound Merino tops are typically 190, the Quince merino base layers are 165, and Smartwool is at 250 GSM.
👕 How to Match Your Base Layer to Your Sweater
✂️ Match the neckline:
✅ Crewneck sweater: wear a V-neck base layer, so nothing peeks out at the collar.
✅ V-neck sweater: a V-neck base layer here too, for the same reason.
✅ Turtleneck sweater: a crewneck base layer, since the turtleneck covers it completely.
⚠️ Wearing a crewneck base layer under a crewneck sweater? Try them on together first, because you don’t want the base layer’s collar sticking out the top.
🎨 Match the color:
❌ Never wear a dark base layer under a light sweater, because it shows through.
✅ Under white, ivory or cream sweaters, go with a white base layer.
💡 Pro tip: try them on together before you pack. My white V-neck still shows under my white wool turtleneck 😅
🎯 Also read: how to layer for cold weather travel, from base layer to coat
🧶 The 9 Best Merino Wool Base Layer Picks for Women (Plus My Husband’s)
The Unbound V-neck and tights are mine, number 9 is my husband’s, and the rest are picks for different needs and budgets (I haven’t worn those myself).
🧵 The Best Long Sleeve Base Layers
1️⃣ Best Merino Wool Base Layer on a Budget: Quince Long Sleeve
Best for: trying merino without paying premium merino prices.
The Quince women’s merino base layer long sleeve is a more affordable way into merino than the bigger merino brands.
💡 If you’re not sure merino is for you, start here. Once you know you love it, upgrade the one piece you wear most.
2️⃣ The Premium Pick I Wear: Unbound Merino Slim V-Neck
Best for: a merino wool base layer women can tuck in and wear under every sweater.
I own the Unbound Merino Women’s Slim Long Sleeve V-Neck in ivory, slim fit, size S (I’m 5’4″).
I went slim so it tucks in with no bunching at all. And I picked the V-neck because I like that style better when I wear it on its own as my outer layer (personal style opinion 😉).
This is the premium option, and the slightly warmer one of the two.
Heads up: the ivory is a merino and poly blend for a brighter white. If you want 100% merino, go for the black or gray V-neck.
⚠️ The honest tradeoff: my natural deodorant turns the armpits yellow on the ivory. That kind of defeats the purpose of a shirt you don’t need to wash often 😅
If you use natural deodorant too, black or gray will hide it better.
3️⃣ Best Midweight Top: Smartwool Merino 250 Crew
Best for: trips below freezing and long days outside.
The Smartwool Merino 250 base layer crew is midweight, so it’s warmer than the lightweight picks above. It’s also a bit bulkier under a fitted sweater.
💡 Pair it with a chunkier knit or a fleece instead of a fitted sweater, so your arms don’t feel squeezed.
👚 Merino Tees: If You Run Warm
4️⃣ Best Budget Tee: Quince Merino Tee
Best for: a cheaper short sleeve layer for heated trains, museums and restaurants.
The Quince women’s merino base layer tee goes under a cardigan or a sweater.
💡 It’s worth packing on fall and spring trips too, since it works on its own once the afternoon warms up.
5️⃣ Best Premium Tee: Unbound Merino Crewneck T-Shirt
Best for: women who overheat indoors but still want merino on cold days.
A short sleeve merino crewneck tee under your sweater keeps your core warm without trapping you in long sleeves inside a warm museum or restaurant.
💡 Pair it with a cardigan instead of a pullover, so you can take a layer off and still look dressed.
Prefer more room? The relaxed version has a more casual fit, which is better if you’ll mostly wear it on its own.
🎨 Unbound Merino’s tees come in 13 colors, in slim or relaxed fits, so you can match them to the sweaters you already own.
🧳 Not sure what else to pack for your winter trip?
A base layer is one piece. The hard part is building the rest of your winter suitcase around it, so you stay warm without packing five sweaters.
Answer 2 quick questions ⬇️ about your trip, and I’ll send a customized packing list straight to your inbox.
🧦 The Best Merino Wool Base Layer Bottoms: Leggings, Tights and Long Underwear
6️⃣ Best Budget Leggings: Quince Merino Leggings
Best for: an extra warm layer under pants.
The Quince women’s merino leggings are the women’s version of the bottoms my husband wears in pick 9.
I personally prefer tights over leggings, but these are a great option if you’re on the other side of that coin.
They’re 240 GSM and 100% merino, so they’re thicker and warmer than any of the tops on this list. And the Unbound Merino tights below go even further, at 300 GSM.
Unfortunately, these are often sold out 😔 But the merino tights below and the Smartwool bottoms do the same job.
7️⃣ Best Tights for Dresses and Skirts: Unbound Merino Tights
Best for: wearing under dresses and skirts on cold days.
I own the Unbound Merino women’s tights in size S/M. They’re a blend (36% merino with Tencel, nylon and spandex), and they’re one of the softest pieces I own.
They’re thicker than regular thin tights, and warmer (of course). I wear mine under dresses and skirts.
They also work under looser pants that aren’t too fitted. Just skip them under light colored pants.
💡 If you’re looking for thermal underwear women can wear under a dress without looking like ski gear, these merino tights are my pick.
8️⃣ Best Base Layer Pants: Smartwool Merino 250 Bottoms
Best for: snow, ski towns and full days outside below freezing.
If you’d rather have long underwear than tights, the Smartwool Merino 250 base layer bottoms go under jeans or looser trousers.
💡 Midweight bottoms are warm, so save them for your coldest days. In the 40s°F (around 5°C), tights or regular pants are plenty.
🎁 Shopping for Him? I Have You Covered
9️⃣ Best Merino Base Layers for Men
Best for: the merino base layer men in your life will actually wear.
My husband wears the Unbound Merino men’s long sleeve crew in charcoal, size M (he got the tall length, which isn’t always in stock). It’s a thin 17.5 micron jersey, and he says it feels ultra soft.
💡 Charcoal goes under navy, gray and camel sweaters without standing out at the collar.
On the bottom, he wears the Quince men’s merino base layer bottoms in size M under any pants. He says they’re comfy and keep him warm, especially on windy days.
💡 Size by the waist. He went with M because he has a slim waist, and a loose waistband slides around under pants.
🤔 How to Pick the Best Merino Wool Base Layer for Your Trip
✅ You run cold and want one piece for everything: the Unbound V-neck, plus the Unbound tights if you wear dresses.
✅ You run warm: the Unbound crewneck tee or the cheaper Quince merino tee.
✅ You’re trying merino for the first time: the Quince long sleeve.
✅ You’ll be outside all day below freezing: the Smartwool 250 crew and Smartwool 250 bottoms.
✅ You’re shopping for him: my husband’s Unbound crew and Quince merino bottoms.
If you’d rather browse, Unbound also has soft merino basics that layer under everything.
⭐️ What about Uniqlo Heattech? It’s a cheaper synthetic layer, not merino.
It’s thin and warm, but synthetic fabric holds onto smells, so plan on washing it after every wear or two.
🙋♀️ Worried merino will itch? Thin, fine merino usually doesn’t.
I shared my honest take on whether merino wool is itchy after years of wearing it.
🧺 How I Wash and Wear Mine
I wear my V-neck about 3 to 4 times between washes. That depends on how much you sweat, though, and I don’t sweat much because I run cold.
When it’s time, it goes in the wash on delicates, and then I hang it to air dry.
💡 Skip the dryer. Heat can shrink wool, and merino is no exception.
As for how I wear it: under light sweaters on the cold days, on its own on the milder ones, and the tights under dresses and skirts.
🎯 Also read: how merino compares to cashmere for warmth and softness and which Quince coat to layer over it for your temperature
Quick Recap: My Top 9 Picks for the Best Merino Wool Base Layer
- Quince Merino Long Sleeve. The budget way to try merino.
- Unbound Merino Slim V-Neck. Mine, in ivory. Tucks in with no bunching.
- Smartwool Merino 250 Crew. Midweight warmth for trips below freezing.
- Quince Merino Tee. A cheaper short sleeve layer for heated indoor spaces.
- Unbound Merino Crewneck T-Shirt. Merino warmth without long sleeves if you run warm.
- Quince Merino Leggings. The budget bottoms, sold out right now.
- Unbound Merino Tights. My pair for dresses and skirts on cold days.
- Smartwool Merino 250 Bottoms. True long underwear for snow and ski towns.
- Unbound Merino Long Sleeve Crew and Quince Men’s Merino Bottoms. My husband’s picks.
And there you have it. The best merino wool base layer picks for staying warm on your next cold trip.
If you only buy one, go for a thin, fitted long sleeve in a color that disappears under your sweaters.
And if you run warm, a merino tee gets you the same benefits without the long sleeves.
Thanks for reading!
XO,
Aimara
PS: Planning a winter trip? Answer 2 quick questions here and I’ll send you a customized packing list for your trip.
About the author:
Hi, I’m Aimara! I’ve been a full-time carry-on traveler since 2021, and I run cold, so I’m picky about warm layers that pack small.
Here on Ways of Style I share packing lists, capsule wardrobes and honest reviews of the pieces that earn a spot in my suitcase (with my husband’s notes on the men’s side 😉).
MORE COLD WEATHER TRAVEL ARTICLES 👇🏼
- My Cold Weather Travel Packing List (Without Bringing Your Whole Closet)
- Europe Winter Outfits: 10 Cozy Essentials, 30 Looks to Copy
- The Warmest Winter Jackets to Wear Over Your Base Layer
- The Best Quince Coats for Every Temperature
Best Merino Wool Base Layer FAQ
Is the best merino wool base layer worth the price?
For travel, I think so. Merino costs more than synthetic layers, but you can wear it several times between washes and it packs thin, so you bring fewer pieces. If you’re unsure, start with a budget piece like the Quince merino long sleeve.
Does merino wool smell after a few wears?
Merino resists odor much better than synthetic fabrics, so it stays fresh for several wears. How many depends on how much you sweat. Airing it out overnight between wears helps too.
Can you wear a merino base layer on its own?
Yes. A slim, thin merino top looks like a regular long sleeve, and I wear my V-neck on its own on milder days. Thicker midweight tops look sportier, so they work better under something.
Should I get a lightweight or midweight merino base layer?
Lightweight is best for city trips between about 35 and 55°F (2 to 13°C), worn under sweaters. Midweight is for days below freezing or long hours outside. If you run warm, lightweight is almost always enough.
Is merino wool thermal underwear better than synthetic?
Merino wool thermal underwear breathes better and holds onto smells far less than synthetic, which matters when you wear pieces more than once on a trip. Synthetic options like Uniqlo Heattech cost less and dry fast, but they need washing more often.
What’s the best base layer for cold weather if you run cold?
The best base layer for cold weather, in my opinion, is a thin merino long sleeve on top plus merino tights or long underwear on the bottom. Then layer a sweater and a warm coat over it. I explain the full system in my cold weather layering guide.
Is a merino base layer itchy?
Fine merino usually isn’t. My V-neck isn’t itchy at all, and thin jersey knits feel softer than chunky merino sweaters. If wool bothers your skin, read why merino itches for some people and the fix.
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